Refrigerated chambers



Inventor J. C. E. LOWCOCK REFRIGERATED CHAMBERS 5 Sheets-Sheet 1 March l, 1966 Filed oct. 15, 1954 JOHN C. E, LowcacK March 1, 1966 J. c. E. LowcocK 3,237,424

REFRIGERATED CHAMBERS Filed Oct. 15, 1964 5 Sheets-Sheei'l 2 fyi Inventor /HN E, LowcocK March 1, 1966 J. c. E. LowcocK REFRIGERATED CHAMBERS 5 Sheets-Sheet 5 Filed OCb. l5, 1964 Fl' .4. 9 Inventor JOHN LOWCOCK iwf-Adel.

A Harn e y United States Patent O 3,237,424 REFRIGERATED CHAMBERS .lohnChar-lesEdwin Lowcock, Ightham, England, assigner to J. & E. Hall Limited, London, England, a British company Filed-Oct. 15, 1964, Ser. No. 404,100 Claims priority,eapplication Great Britain, ct. 18, 1963, 41,206/ 63; 0st. 23,1963, 41,862/63 v Claims. (Cl. 62-282) Thisinventionrelates to a refrigerated chamber of the kind comprising support means for materialto be cooled inthe chamber, a plurality of air coolers located within the chamber and means for continuously circulating air in the chamber past the heat-exchange surfaces of said coolers and past said support means.

Chambers of the kind specified are used for the freezing of comestibles, cold air being moved in cyclic fashion through the chamber withdrawing thermal energy from the comestibles and losing it to the air-coolers. Since the comestibles normally cooledin such a chamber containxa proportion of water, a deposit ofv ice is built up on theheat-exchange surfaces -of the air-coolers during operation :of the chamber. These ice deposits impair the heatexchange eiciency of the air-coolers and have to be either prevented from forming'or periodically removed'in a defrostingoperation in which the melted ice is collected in a drip tray located beneath the cooler.

Preventing the formation of ice deposits is commonly effected by continuously washing the heat-exchange surface.s. with ahygroscopic defrost solution. The solution issprayedon the heat-exchange surfaces -of the air-cooler and is then collected in a drip tray locatedbeneath the airv cooler. This methodof operation will be hereinafter referred Vto as continuous defrosting.

Where the airl circulating in the chamber moveswith high velocity there is obviously a possibility, when employing continuous defrosting and using a spray of a defrost solution, that droplets of solution will become entrained in the air flow and .carried on to the comestibles. A refrigerating chamber in accordance with the invention, because of a novel positioning -of the lower opening or openings for the main stream -of air owing frornfthe aircooler, allows in the preferred arrangement, ay highly efficient removal of defrost solution from the air flowing through the cooler and thus facilitates the limiting of defrost solution to the close proximity of the air-cooler when continuous defrosting is employed.

Where, in place of continuous defrosting it is desired to defrost the, air coolers periodically, the air-coolersare usually isolated `one at a time from the main body of cold air circulating in the chamber while they are defrosted, the low temperature in the chamber being maintained by the other air-coolers duringthis operation.

The periodic isolation of the air-coolers from the circulating air ilow is normally accomplished by means of shut-off valves which are sited one upstream and one downstream of the cooler. These valves prevent any appreciable air flow through the cooler being defrosted, and help'to keep the water employed in, and/or created during, the defrosting from increasing the humidityA of the remainder ofthe air in the chamber.

3,237,424 Patented Mar. l, 1966 ICC The shut-off valves used heretofore have normally been pivoted ap valves or sliding shutters, both -of which have, in at least some respects, proved to lbe unsatisfactory.

The flap-valves or sliding shutters tend to collect ice and'can become stuck in a particular position (i.e. fully open or fully closed). Further it has proved difficult to arrange for a satisfactory automatic system -for the operation of these pivoting or sliding shut-off valves.

The presen-t invention relates to a refrigerated chamber of the kindl specified which lends itself to highly ecient operation with either continuous or periodic defrosting.

According to the present invention, a refrigerated chamber of the kind specified comprises a casing extending downwardly fromthe air-cooler anddefning a duct for lair flowing from the cooler and containing a drip tray for defrost solution, thev lower opening or openings for the main stream of air owing through said casing 'being located'abovethe lowest pointof, and within the vertical confines of, thev drip tray.

A chamber in accordance with-the invention may contain a plurality of air-coolers which may each be located in a separate casing, may bewsub-divided in groups with each` group' located in a separate casing, or, if only continuous defrosting is employed, may all be located in a single casing.

Where there are a plurality ofV air-coolers in a casing, preferably one openingfor each air-cooler is provided eachy openingbeing-located substantially centrally below the respective air-cooler. In this manner itis possible to arrange for the paths of air owingbetween the cooler and the respectivev opening to besubstantially- S-shaped.

In the case of periodic:l defrosting, each air opening within the driptray is provided with a shut-olf valve which, in a p referredfarrangement, is readily adapted to automatic control and is more positive in operation. Such a shut-off v-alve comprises-.a closure membermovable towards and away from a cooperating valve seating deningthe openingl or one' of theV lopenings for the mainstream of airowing from the air-cooler, the seating beingflocatedfabove the lowest part of,- and within the vertical confines of, the drip tray.

Preferably theY closure member and the cooperating valve seating are. located directly below the air-cooler and if desired the'closure'memberl may be positioned'so as to be washed by water flowing fromthe-cooler during defrosting. Preferably the closure member is mounted von aneactuating shaftfand the-opening and closing movements ofthe closure-^member are made'in a direction whichis substantially at right angles to-the plane yof the seating.

In a-preferredarrangement, the shut-otf valve below theY air-cooler is'coupled with aA second valve disposed above the air-cooler, the closuremembers of the two shut-offfvalves being movable together into and lout of engagementawith their respective cooperating seatings.

Byarrangingfor the closure memberto lbe washed by water it can-be arranged that the temperature of the closuremember is raised above freezing pointvduring the defrostingoperation. Itcanthusbe arranged that there is no ice sealing the closure member. to the cooperating valve-seatingwhenl the time cornes to resume air circulation through-the cooler.

TheI invention will now be further described byy the following two embodiments, which are given by way of exchange surfaces of the cooler.

3 example, with reference to the accompanying drawings, in which:

FIGURE l is a schematic sectional transverse view of a refrigerated chamber of the kind specified.

FIGURE 2 is a partial plan froml above of the chamber of FIGURE 1 with the roof of the chamber removed,

FIGURE 3 is a sectional view on an enlarged scale of part of the chamber of FIGURE 1 designed to operate with continuous defrosting, and

FIGURE 4 is a sectional view similar to FIGURE 3 showing how the chamber is modified to operate with periodic defrosting. 4 Referring to FIGURE l, the refrigerated chamber is formed with thermally insulating walls, roof and oor and is provided with an inlet 1 for comestibles fed to the chamber, an outlet for comestibles issuing from the chamber (not shown, but located in the opposite end wall to that in which the inlet is located) and an air-permeable support 2 within the chamber leading from the inlet 1 to the outlet. Disposed within the chamber are a plurality of air-coolers 4 and a plurality of fans 5 for circulating the air in the chamber so that it ows upwards through the support 2 and downwards past the air-coolers 4. Also located within the chamber are a plurality of wheeled trolleys 3 on which packets of frozen comestibles may be stored.

Referring now to the embodiment of FIGURE 3, it will be seen that each air-cooler is located at the upper end of a casing 6 forming a duct for cooled air flowing 4downwards from the cooler 4. Each air-cooler is disposed below spray means 7 adapted to spray a defrost solution (eg. propylene glycol and water) over the heat- Owing to the low freezing point of the solution, ice formation on the air-coolers is thereby prevented.

Deector plates 8 are located below the air-coolers and are positioned to divert the downwardly flowing air and the entrained droplets of defrost solution towards the side walls of the casing and through rst plate-type spray-eliminators 9. In passing through the first sprayeliminators (which are of a conventional design) a high proportion of the entrained droplets are separated from the air stream and are drained to the side walls of the casing and pass through a duct 101.

Located below the deflector plates 8 and positioned to collect defrost solution pouring off the lower edges of the plates 8 is an auxiliary drip tray 11.

The bottom of the cooler casing comprises an inclined plate 12 forming the main drip tray for the defrost solution. After passing through the first spray-eliminators 9, the air flows downwardly towards the inclined plate 12 and is then made to execute a substantially complete reversal of direction, turning inwardly of the casing to flow across the inclined plate and then upwardly to ow through second spray-eliminators 13 located below the first spray-eliminators 9.

Once through the second spray-eliminators 13, the air, now substantially free of entrained droplets, executes a second substantially complete reversal of direction, lirst turning to llow inwardly of the casing again and then turning to flow downwardly through an opening 14 forming the main air outlet of the casing 6. Each outlet, and in this specific embodiment of the invention there are a number spaced lengthwise of the casing, is located centrally with respect to -the transverse dimension of the casing. The outlet 14 is positioned directly beneath the deflector plates 8 and is shielded thereby from the main spray of defrost solution falling from the air-cooler, and is also raised above the level of the inclined plate 12 forming the drip tray of the cooler.

Defrost solution collected in the auxiliary drip tray 11 drains down to the main drip tray via a tube 15.

It will be appreciated that by locating the air opening 14 within the drip tray 1,2 a very compact arrangement results which enables a double reversal in the direction of air flowing from the air-cooler to the opening. In practice it is found that by making the air-ow direction reverse, particularly by making it change suddenly from a downward to an upward direction, enhanced droplet extraction is obtained. The moment of inertia of the droplets entrained in the downwardly flowing air after passage through the spray-elirninators 9, tends to cause the droplets to leave the air stream when the latter reverses direction above the surface of the main drip tray.

The embodiment described with reference to FIG- URE 3 is an embodiment designed to operate with continuous defrosting. FIGURE 4 shows how a chamber in accordance with the invention can be employed to operate with periodic defrosting. Referring to FIGURE 4, and employing, where applicable, the same reference numerals as employed in FIGURE 3, each air-cooler 4 is associated with two shut-olf valves one (16) which closes the inlet, or upper end, of the casing 6 and one (17) which closes the outlet, or lower end, of the casing. The arrangement of shut-off valves is the same for each air-cooler in the chamber and for convenience, the arrangement with reference to just one of the coolers will be described.

The two shut-off valves 16 and 17 each comprise a movable closure member 16a and 17a and a fixed cooperating valve seating 16b and 17b. The two closure members 16a and 17a are mounted on an axially movable vertically disposed elongated support 18, closure member 17a being `substantially rigidly fixed to the support 18 and closure member 16a being resiliently attached to the support 18 via a spring 19 to allow a degree of movement in the elongated direction of the support.

The lower shut-off valve 17 is formed on an annular gutter 20, the central aperture of which forms the opening 14 for air flowing downwards from the cooler 4. The closure member 17a of the lower shut-olf -valve is a dome-shaped cap supported above the gutter 20 with its convex surface uppermost. The cap is located directly above the opening 14 in the gutter, the underside of the cap, and a seating around the innermost edge of the gutter, being formed as cooperating air-seal surfaces. The cap, when pressed against the seating on the gutter, seals the aperture therein and for-ms a drip tray 12 for the cooler.

Located below the gutter is a chamber 21 in which the fan 5 is located and in which the air-flow changes from the vertical to the horizontal direction.

The closure member 16a of the -upper shut-off valve is a part spherical cap having a sealing ring formed on its convex surface. The sealing ring is .adapted to engage, in the closed position of the valve, with the cooperating seating 16h delining the main air inlet to the casing 6. As hereinbefore described, the closure member 16a is mounted on the support 18 to allow a measure of resilient movement in the axial direction. The spacing between the sealing rings of the upper closure member 16a and the lower closure member 17a is, in the open position of the valves, arranged to be slightly less than the separation of the cooperating seating surfaces of the two valves, so that when the support 18 moves axially downwards to close the Valves for defrosting the cooler, the resiliently mounted closure member 16a closes first and is then urged with an increasing force against its cooperating seating 16h as the closure member 17a completes its closing movement. Similarly, it follows that when the support 18 is moved upwards to open the valves, it is the closure member 17a which is lifted clear of its cooperating seating 17b first. By arranging the two closure members on a single support in this way it has proved a comparatively simple matter to arrange for automatic operation of the valves.

The preferred method of defrosting the air-cooler 4 is to wash the heat-exchange surfaces with water sprayed on to the cooler from suitable sprinklers. Where this method is employed, it follows that an appreciable volume of water will flow from the cooler into the drip tray 12 before a defrosting operation is completed. By locating the closure member 17a of the lower valve in the centre of the drip tray, it follows that a considerable proportion of the water flowing from the cooler flows over the convex surface of the cap (and then into the gutter and to waste via a pipe 23) and has the effect of raising the temperature of the closure member 17a to above freezing point. Preferably however heating means (not shown) is provided in association with each valve seating, although when defrosting by water spray, the thermal capacity of the water supplied to the cooler is normally found to be more than adequate to ensure that the closure member 17a is free from ice at the conclusion of the defrost and it is not normally necessary to supply additional heat to the seating of the lower valve from the respective heating means. When defrosting is effected by heatingthe aircooler, a much smaller volume of water flows into the drip tray during defrosting and in these circumstances it is advisable to augment the heating effect of the water with the heating means. Where defrosting is effected by heating the cooler, there may be advantage in shielding the closure member of the lower valve from direct contact with water flowing from the cooler, for example by providing deflector plates 8 (shown dotted).

The sprinklers for the water spray, which I prefer to employ, may be located in a position fixed relative to the cooler, or they may be incorporated in the closure member 16a as shown at 22. This illustrated .arrangement has the advantage of ensuring that the closure member 16a, as well as the closure member 17a, is maintained at a temperature above freezing by the waterspray, at least at the end of the defrost operation when the valves require to be opened. The supply of water to the sprinklers 22 is made via flexible pipe 24.

Clearly many modifications could be made to the specific embodiment described with reference to FIGURE 4. For example the closure members 16a and 17a need not be cap-shaped and need not be disposed on a vertical support. Although the upper closure member 16a is conveniently provided with a convex lower surface (thus facilitating the incorporation of sprinklers in the closure member) it clearly need not be so shaped.

The operating support 18 for the closure member of the two shut-off valves has been shown extending downwardly into the chamber from above, clearly, however, the operating support could be made to extend upwardly through the bottom of the chamber. Further two separate supports could be employed, the closure member 17a being mounted on a support extending upwardly through the bottom of the chamber and the closure member 16a being mounted on a support extending downwardly from the top of the chamber.

I claim:

1. A refrigerated chamber comprising thermally insulating walls, roof and floor, support means within the chamber for material to be cooled therein, at least one air-cooler within the chamber and fan means for continuously circulating air in the chamber past said aircooler and past said support means, said chamber including a casing housing said air-cooler and extending downwardly and upwardly therefrom, said casing thereby forming a duct for air flowing to .and from the cooler, an upper valve seal defining the inlet to the casing, a drip tray defining the lower end of said casing with at least one opening in the drip tray forming the outlet for air from the casing and defining a lower valve seal, said outlet being located `above the lowest point of, and within the vertical confines of, the drip tray, an upper shut-off valve disposed above the air-cooler and movable into and out of sealing engagement with said upper valve seal, a lower shut-off valve disposed below the air-cooler and movable into and out of sealing engagement with said lower valve seal, and a support extending through the chamber normal to the sealing surfaces of the valves and 6 serving to couple the upper and lower shut-oli valves together.

2. A refrigerated chamber comprising thermally insulating walls, roof and floor, air permeable support means within said chamber for material to be cooled therein, at least one air-cooler within said chamber and fan means for continuously 'circulating 'air in said `chamber past said air-cooler and upwardly through said support means, said chamber including a casing housing said air-cooler and extending downwardly and upwardly therefrom to form a duct for air flowing to and from said cooler, an upper valve seat defining a top opening of said casing, a drip tray defining the lower end of said casing and having at least one opening for `air flowing through said casing, said opening in the drip tray defining a lower valve seat and being located above the lowest point of, and within the vertical confines of, said drip tray, an upper shut-off valve disposed above said air-cooler and movable into and out of sealing engagement with said upper valve seat, a lower shut-off valve disposed below said air-cooler and movable into and out of sealing engagement with said lower valve seat, and a support extending through said chamber substantially normal to the sealing surfaces of said valves and serving to couple the upper and lower shut-off valves together.

3. A refrigerated chamber comprising thermal-ly insulating walls, roof and floor, air permeable support means within said chamber for material to be cooled therein, at least one air-cooler within said chamber and fan means for continuously circulating air in said chamber past said air-cooler and upwardly through said support means, said chamber including a casing housing said air-cooler and extending downward-ly and upwardly therefrom to form a duct for air flowing to and from said cooler, an upper valve seat defining a top Opening of said casing, a drip tray defining the lower end 0f said casing and having at least one opening for air flowing through said casing, said opening in the drip tray defining a lower valve seat and being located above the lowest point of, and within the vertical confines of, said drip tray, an upper shut-off valve disposed above said air-cooler and movable into and out of sealing engagement with said upper valve seat, a lower shut-off valve disposed below said air-cooler and movable into and out of sealing engagement with said lower valve seat, and support means extending through said chamber substantially normal to sealing surfaces of said valves and supporting said shut-off valves for movement in a direction substantially normal to said valve seats.

4. A refrigerator chamber comprising thermally insulating walls, roof and floor, air permeable support means within said chamber for material to be cooled therein, at least one air-cooler within said chamber and fan means for continuously circulating air in said `charn'ber past said air-cooler and upwardly through said support means, said chamber including a casing housing said air-cooler and extending upwardly and downwardly therefrom to form a duct for air flowing past said cooler, a drip tray defining the lower end of the casing and being formed with an air opening therethrough defining a lower valve seat, said opening being located above the lowest point of, and within the vertical confines of, said drip tray, and a lower shut-off valve disposed below said air-cooler and movable in a direction normal to said valve seat into and out of sealing engagement therewith.

5. A refrigerated chamber comprising thermally insulating walls, roof and floor, air permeable support means within said chamber for material to be cooled therein, at least one air-cooler within said chamber, means for continuously circulating air past said air-cooler and upwardly through said support means, said air-cooler being disposed within a casing through which air flows during its circulation within said chamber, spray means for spraying a defrosting solution over said air-cooler, a drip tray disposed below said air-cooler to collect solution dripping from said air-cooler, said drip tray containing an air valve movably in substantial-1y vertical direction and positioned .above the lowest point of said drip tray and within the vertical connes thereof beneath said air-cooler to be washed by defrosting solution dripping into the drip tray during a defrost operation.

References Cited by the Examiner UNITED STATES PATENTS 175,291 v3/1876 Loum 62-.82

Rogers 62-288 Cook 62-82 Conn 62-419 Knowles 62-419 Morgan 62-282 Brouse 62-282 Zellner 62-82 Rollins 62--309 2/ 1929 Knauss 62-285V 10 WILLIAM J. WYE, Primary Examiner. 

5. A REFRIGERATED CHAMBER COMPRISING THERMALLY INSULATING WALLS, ROOF AND FLOOR, AIR PERMEABLE SUPPORT MEANS WITHIN SAIDS CHAMBER FOR MATERIAL TO BE COOLED THEREIN, AT LEAST ONE AIR-COOLER WITHIN SAID CHAMBER, MEANS FOR CONTINUOUSLY CIRCULATING AIR PAST SAID AIR-COOLER AND UPWARDLY THROUGH SAID SUPPORT MEANS, SAID AIR-COOLER BEING DISPOSED WITHIN A CASING THROUGH WHICH AIR FLOWS DURING ITS CIRCULATION WITHIN SAID CHAMBER, SPRAY MEANS FOR SPRAYING A DEFROSTING SOLUTION OVER SAID AIR-COOLER, A DRIP TRAY DISPOSED BELOW SAID AIR-COOLER TO COLLECT SOLUTION DRIPPING FROM SAID AIR-COOLER, SAID DRIP TRAY CONTAINING AN AIR VALVE MOVABLY IN SUBSTANTIALLY VERTICAL DIRECTION AND POSITIONED ABOVE THE LOWEST POINT OF SAID DRIP TRAY AND WITHIN THE VERTICAL CONFINES THEREOF BENEATH SAID AIR-COOLER TO BE WASHED BY DEFROSTING SOLUTION DRIPPING INTO THE DRIP TRAY DURING A DEFROST OPERATION. 